Systems for the treatment of impurity-containing water have been many and varied over the years. Environments where water treatment systems are used range from the large scale, such as water reservoirs, ponds, lakes and sewage treatment plants to the small scale such as domestic septic tank systems, water tanks, ponds and pools. In all of these applications, the aim of the treatment process is to remove or neutralise organic contaminants, such as plant or animal derived matter, sewage and pathogens, or inorganic impurities, including metal ions, phosphates and nitrates. The measurement of water quality arising from the treatment include total suspended solids (TSS), biological oxygen demand (BOD), total nitrogen (TN), total coliform, dissolved oxygen (DO) and concentration of inorganic species.
In the case of sewage treatment, the systems previously used in the treatment of sewage have ranged from simple, purely anaerobic septic tanks to complex filter systems incorporating multiple filter beds, in which both anaerobic and aerobic bacterial activity can sequentially consume nutrients, remove contaminants and leave the water in a purer form.
It is often a common feature of the simple septic tank that effluent which is released into a dispersal field system of soakage drains is exceedingly high in all undesirable qualities that are routinely taken as a measure of water quality, namely TSS, BOD, total nitrogen and total coliform.
It is also often a common feature of the more complex systems of contaminated water treatment that measurements of these parameters exceed local authority maximum allowable levels.
Systems that will regularly achieve lower counts than the maximum allowable are often expensive to install and require a rigorous and expensive maintenance regime throughout the entire life of the system.
Systems for the removal of inorganic contaminants are typically quite different to those for organics removal and usually involve thermal, membrane, or electrolytic technologies. These too are often complex and involve the expense of large quantities of energy and high maintenance costs.
Moreover, the removal of both organic and inorganic impurities typically cannot be effected by using a single method or system, which complicates the treatment of water containing both types of impurities.
It is accordingly an object of the present invention to provide a method for the treatment of impurity containing water which overcomes, or at least alleviates, one or more disadvantages of the prior art.